Tag Archives: Antibody

South African and Brazilian SARS-CoV-2 variants showed resistance to therapeutic antibodies | Instant News


A team of scientists from Germany has decided efficacy therapies currently used in treating a new variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including variants B.1.1.7 (UK), B.1.351 (South Africa) and B.1.1.248 (Brazil) ). Their findings reveal that variants B.1.351 and B.1.1.248 can escape a humoral immune response induced by therapeutic antibodies, vaccinations, or natural SARS-CoV-2 infection. Studies are currently available at bioRxiv* preprint server.

Background

Since its emergence in December 2019, the highly contagious and deadly SARS-CoV-2, the pathogen that causes coronavirus disease 2019 (COVID-19), has infected more than 108 million people and claimed more than 2.3 million lives globally. In the global effort to control the spread of the virus, a lot of research has been done to find effective therapeutic strategies against COVID-19. Currently, several antiviral drugs and reused therapeutic antibodies are used to treat critical COVID-19 patients. As a protective measure, several potential vaccines targeting the viral spike protein have received emergency use approval from the relevant authorities.

In the next phase of the pandemic, several new variants of SARS-CoV-2 have emerged, including variants B.1.1.7 (UK), B.1.351 (South Africa), and B.1.1.248 (Brazil). Several mutations found in these variant spike proteins have been found to significantly increase their infectivity. Additionally, there are preliminary studies suggesting that this variant may be more virulent and is likely to increase the mortality rate related to COVID-19. Since most of the antibodies and therapeutic vaccines currently available primarily target the SARS-CoV-2 protein spike, potential concern is increasing about the effectiveness of current therapeutic interventions in preventing the spread and death of the emerging variant.

In the current study, scientists have evaluated the effectiveness of viral entry inhibitors, monoclonal antibodies, and vaccines in preventing infection by British, South African, and Brazilian SARS-CoV-2 variants.

Study design

Scientists use human and animal cell lines to do this in vitro trial. To analyze the effectiveness of virus entry inhibitors against the SARS-CoV-2 variant, they used angiotensin-converting enzyme 2 (ACE2), cellular protease inhibitors (TMPRSS2), and membrane fusion inhibitors (EK1 and EK1C4). To determine whether this variant is resistant to the humoral immune response, scientists thoroughly analyzed the efficacy of anti-SARS-CoV-2 antibodies obtained from three types of sources: 1) therapeutic monoclonal antibodies (Casirivimab, Imdevimab, and Bamlanivimab); 2) plasma samples collected from critically ill COVID-19 patients; and 3) serum samples collected from people vaccinated with the BioNTech / Pfizer vaccine (BNT162b2).

An important observation

Although there is evidence to suggest increased transmission of the emerging SARS-CoV-2 variant, current research scientists have not observed any significant differences in host cell entry dynamics between wildtype viruses and British, South African, and Brazilian variants. In particular, the wildtype spike protein and all tested variants of SARS-CoV-2 showed comparable efficiency in entering host cells.

Interestingly, the entry of wildtype variants and mutations into host cells was significantly blocked by dissolved ACE2, TMPRSS2 inhibitors, and inhibitors of membrane fusion. Compared with the wildtype virus, the variant shows a higher susceptibility to soluble ACE2-mediated inhibition. Likewise, the Brazilian variant showed a higher susceptibility to membrane fusion inhibitors. These observations suggest that virus entry inhibitors may potentially be used to prevent infection mediated by the mutated variant of SARS-CoV-2.

Although showing comparable cell-virus interaction dynamics, significant differences in antibody-mediated neutralization were observed between wildtype viruses and mutated variants. Among the monoclonal antibodies tested, Imdevimab demonstrated comparable efficacy in inhibiting entry of host cells by all viral variants. In contrast, the South African and Brazilian variants exhibited partial and complete resistance to Casirivimab and Bamlanivimab. However, all the antibodies tested showed high potency in inhibiting the British variant.

Neutralizing antibodies generated in response to SARS-CoV-2 infection is expected to provide protection against reinfection. To determine efficacy recovery plasma For the treatment of viral variants, COVID-19 plasma samples obtained by patients with high neutralizing properties of the wild-type spike protein were tested against all virus variants. The findings revealed that entry of host cells via spike proteins from the South African and Brazilian variants was less efficiently inhibited by the majority of the plasma samples tested. This suggests that people previously infected with the wildtype SARS-CoV-2 were only partially protected from the South African and Brazilian variants.

Regarding vaccine-mediated protection, the findings reveal that a large proportion of serum samples obtained from BNT162b2 vaccinated individuals had a lower efficiency in inhibiting surge-driven entry of host cells compared to that observed for wild and variant SARS-CoV-2 strains and variants. English.

Learn significance

The study revealed that current therapeutic interventions are less effective in inhibiting the SARS-CoV-2 variants of South Africa and Brazil, and thus, rigorous implementation of non-pharmaceutical control measures is needed to contain transmission.

* Important Notice

bioRxiv publishes preliminary scientific reports that are not peer reviewed and, therefore, should not be considered a convincing guide, guide health-related clinical / behavioral practice, or be treated as defined information.

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Italian regulators approve the conditional use of COVID-19 antibody therapy | Instant News


MILAN (Reuters) – Italian drug regulator AIFA has given the green light for emergency use of the COVID-19 antibody therapy developed by US drug makers Eli Lilly and Regeneron, he said on Friday.

Treatment is aimed at patients with mild to moderate disease who are at risk of their condition worsening, said the AIFA.

The regulatory scientific committee said it was appropriate to provide this treatment option, while also showing that data was not well developed and there was uncertainty about how much benefit the drug could offer.

“This is a high-risk setting for which no standard treatment with proven efficacy is currently available,” said AIFA, noting that approval was overwhelming because of the emergency situation.

The EU regulator said on Thursday it was reviewing data on Eli Lilly and Regeneron antibody therapy.

The casirivimab and imdevimab Regeneron cocktails were permitted for emergency use in the United States in November, and were given to former US President Donald Trump when he became ill with COVID-19.

Eli Lilly’s combination therapy of two antibodies, bamlanivimab and etesevimab, helps reduce the risk of hospitalization and death in COVID-19 patients by up to 70%, data from a late-stage trial showed in January.

Reporting by Emilio Parodi; Edited by Frances Kerry

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Viral-fighting antibodies persist in New Zealand’s Covid-19 patients | Instant News


Viral-fighting antibodies have been found in Kiwi Covid-19 patients for up to eight months after they were infected – a finding that could bode well for the upcoming vaccine rollout.

The new research, released before peer review, has also proven to be of global importance, given that antibodies persist even when no viruses are circulating in the community.

The study analyzed antibodies in a group of 112 New Zealand patients previously infected with the SARS-CoV-2 virus, most of whom had mild symptoms.

Antibodies play an important role in the immune system against pathogens such as the coronavirus.

Once a new virus is recognized, antibodies are specially crafted to bind to the “spike protein” and stop it from entering our cells – while signaling other parts of the immune system to destroy foreign invaders.

“Because antibodies are very specific for an invading pathogen or virus, they also provide a way to track and study a person’s history of infection,” said Dr. Nikki Moreland, an immunologist and biomedical scientist at the University of Auckland.

“In other words, by taking a blood sample of someone, and seeing if there are specific antibodies for SARS-CoV-2 in circulation, it’s possible to determine if they have previously had Covid-19.”

This is useful for diagnosis – especially when the swab has no more virus due to infection several weeks or months ago.

“By studying the level and function of circulating antibodies, it is also possible to determine whether a person has the types of antibodies that might provide protection if they encounter certain viruses or pathogens again.”

The new collaborative study, carried out by PhD student Alana Whitcombe and research scientist Dr Reuben McGregor on the Moreland team, investigates not only the quantity of antibodies in previously infected people – but also their quality.

“Specifically, do people have antibodies that bind to viral spike proteins, can these antibodies neutralize the virus, and how long do these antibodies last?” McGregor said.

In the laboratory, the researchers measured levels of circulating antibodies that bind to spike proteins, as well as whether those antibodies neutralized.

“Since we had samples from people who were infected months earlier, we can use this measurement to see how long the antibodies last.”

Antibodies play an important role in the immune system against pathogens such as the coronavirus.  Photo / 123RF
Antibodies play an important role in the immune system against pathogens such as the coronavirus. Photo / 123RF

“The good news is we observed that the majority of people have neutralizing antibodies that bind to the spike protein and they can be detected for up to eight months after infection.”

While overseas research shows this too, the main difference is that this effect has been demonstrated in countries where Covid-19 has been successfully eliminated.

“People in New Zealand are not re-exposed to the virus like they are in countries with high community transmission rates,” Moreland said.

When someone is re-exposed, he explained, their immune system boosts, which can affect levels of circulating antibodies.

That makes similar data from abroad more difficult to interpret, given it’s unclear whether antibodies were there simply as a result of re-exposure.

“In New Zealand we are fortunate not to have that problem to consider when looking at our data,” said Moreland.

“We believe the antibodies we measured came from the initial infection, so seeing these antibodies last up to eight months was really encouraging.”

What does the vaccine launch mean?

Moreland said the study offers some “positive signals”, given the data from vaccine trials showing the agent induces similar – and in some cases higher – levels of neutralizing antibodies for natural infections.

“So the protection from the vaccine is also likely to last for months and maybe even longer,” he said.

“But we are still studying in real-time, every month we see that the antibodies last one month longer.

“Also, there are several different vaccines and it is important to track the antibody response to different vaccines to measure whether there is a difference in the quality and quantity of the antibodies they produce, and how long the neutralizing antibodies to vaccines last.”

Further studies showed that scientists could accurately measure spike antibodies from finger prick blood samples.

“This could drastically improve the feasibility of large-scale studies to track vaccine antibody responses.” Whitcombe said.

The paper, uploaded to medRxiv’s pre-print server, involved doctors and scientists from the University of Otago, New Zealand Blood Service, Te Punaha Matatini, Callaghan Innovations, the Maurice Wilkins Center, Southern Community Laboratory and the City of Auckland, Starship and Kidz First Children’s Hospital .

“This work would not have been possible without a national network of doctors, nurses, researchers and scientists and highlighted the collaborative nature of New Zealand’s science during the pandemic,” said Moreland.

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Wuhan Covid-19 cases may be 10 times higher, studies show | Instant News


File scale Covid-19 outbreak in Wuhan earlier this year may be nearly 10 times the tally recorded, a study conducted by China’s public health authorities showed leaving the city where the coronavirus first struck is far from immunity necessary to protect against potential awakening.

About 4.4% of those tested were found to have specific antibodies that can fight the pathogen that causes Covid-19, indicating that they had been infected at some time in the past, according to a serological survey of more than 34,000 people conducted in April by China. Centers for Disease Control and Prevention. The data was released Monday night.

That ratio shows that with Wuhan Home to around 11 million people, as many as 500,000 residents may have been infected, nearly 10 times more than the 50,000 confirmed cases of Covid-19 reported by health authorities in mid-April, when the survey was conducted.

China has been criticized internationally for its early handling of the outbreak, which has spread around the world in a global pandemic since the first cases emerged. The US has raised questions about China’s tally of the fallout for the virus in Wuhan, which was quickly eclipsed by larger outbreaks in Europe and North America. The revised numbers of cases and deaths added to suspicions that China was massaging the figures.

While serological data may revive those claims, it is common for health authorities not to report cases during an acute outbreak, given that testing capabilities can be limited and hospitals overwhelmed by sudden spikes in patients. The ability of the coronavirus to infect people secretly without making some of them sick until later or even during periods of infection only exacerbates the problem.

Serological surveillance has been widely used by health professionals around the world to measure the true scale of the epidemic, from Covid-19 to AIDS and hepatitis. The prevalence of diseases stemming from these studies can serve as guidelines for mitigation and vaccination efforts.

The Chinese CDC survey showed much less impact of the virus outside of Wuhan, which was effectively shut off as a way to contain the outbreak. The positive rate for antibodies fell to 0.44% for the wider Hubei province, which is also on lockdown for three months. Only two people tested positive for antibodies among 12,000 surveyed in six other Chinese cities and provinces, including Beijing, Shanghai and Guangdong, showing a very low prevalence of the virus nationwide.

The results for Wuhan mean even China’s worst hit cities are still vulnerable to Covid-19. Epidemiologists say at least half the population should be in contact with the virus even for the minimum threshold of herd immunity. But the city’s infection rates are generally in line with those found in other countries following the first wave of coronavirus infections, China’s CDC said in a press release published on its website.

Antibody-positive levels in Spain and Switzerland this spring, for example, were 6.2% and 11%, respectively, the Chinese CDC said. While those were higher than the 4.4% found in Wuhan, and came before later waves hit Europe, they still fell short of the threshold for herd immunity.

Since putting down the Hubei outbreak, China has largely contained the coronavirus, with sporadic turmoil since April being quelled through aggressive contract tracking and rapidly testing millions of people on a daily basis.

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Lonza is planning 2 production sequences for the antibody drug conjugate on the Swiss site | Instant News


The search for next-generation oncology therapies has sparked an arms race in biopharma to find the next big thing – whether it’s in cell and gene therapy or the promising drug-antibody conjugate (ADC). Eyeing the bustling marketplace, Swiss manufacturing giant Lonza plunged further into ADCs with new customers inside.

As part of a bond with an undisclosed customer, Lonza will build two 16,146-square-foot manufacturing suites are dedicated to the commercial production of two cancer-fighting ADCs, the company said Wednesday. The latest expansion at Lonza Visp, Swiss facilities will be online by the end of 2022 and will eventually employ 200 workers.

With a growing number of approvals in recent years, ADC has become a major target of biopharma investment even though the manufacturing process is highly specialized for producing it. Products such as Trodelvy from Gilead Science and Enhertu from AstraZeneca are blockbuster candidates, according to analysts, with the potential for more winners in the near future.

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